Hi, Wedge...
We just got back with our 6-year-old DD, who wears hearing aids for a moderate-severe loss. Her hearing aids have both FM and telecoil capabilities.
She is totally oral, and only uses what we call "survival sign". She is very good at speech-reading...well, to put it more clearly, she is rather dependent on speech-reading.
At Disney, this trip and in the past, we found accommodations for little ones a bit lacking. (Of course, it's better than in the "real" world, but this big new generation of early-identified, technology-aided kids is feeling the pain in trying to find and use auditorally-accessible information with their hearing aids or CIs.) At several parks, we were offered ALDs that use headphones. Those don't work with hearing aids. We didn't have much luck finding anything that worked telecoil-ly.
Of course, captioning doesn't help at this young age. And lots of Disney is LOOOOUUUUUUDDDDDD! We specifically went to the audi before the trip to change hearing aids settings to allow DD to lower the volume on her aids much more than normal. Even so, she spent a fair amount of time with her aids off because it was so loud. And she's not the type of kid who EVER does that.
So, what did we do? We got a GAC that was appropriate for speech-reading. I do wish I had used it more often than we did, as there were some occasions where I chose not to use it (the special treatment factor and/or my lack of awareness of how it could be used at an attraction) and later realized that it would have been helpful. We can share more info by PM, if you'd like.
We also used her personal FM system. We would set it to FM only, as opposed to FM+microphone, and then I would "orally interpret" for her, whispering things that had been said.
We only had one rather minor problem at Beauty and the Beast, where the first CM we approached (the one you are supposed to share the GAC with) couldn't understand what we needed (or rather, didn't want to listen to what we were saying or what the card showed), and kept trying to tell us to come back for the signed show. He finally gave up and sent us on up the hill, where we found someone who "got it". Oh, and on the Jungle Cruise, it was hard to explain what we needed, and try to get them to "fix" it when they did exactly the opposite of what we needed. Just kind of gave up on that one.
As a generality, on the rides, the first CM we approached told us to see the next CM, and then by that time, we were in the midst of the loading/moving process, and those CMs didn't have time to listen. Next time, I would be a little more forceful in explaining needs and not get rushed onto rides without the appropriate situation.
At waterparks, I generally went first on rides, and explained to the CMs that she couldn't hear their instructions (since she didn't have her aids on). They were very matter-of-fact about showing her what to do when it was her turn....no issues at all. We also made sure to watch what others did first, so she would know what to expect.
Oh, and we carried a little brimmed hat with us everywhere, so if we were caught in the rain, her hearing aids would be protected for at least a little bit.
I hope this doesn't sound too negative. It's not meant to be. It's more of a critique of our handling of things, and just the current times for these kiddos.
P.S. My daughter turned her hearing aids off this morning during Spongebob, and told me, "Mom, I'm going to practice reading closed captioning now." I think she's gearing up for our next Disney trip, because I showed her the reverse, mirror captioning that exists in some attractions.